Combined Porous Mesh Metals and Products Made fromThem

In this paper are considered the essence and design-technological features of products made from new types of porous mesh metals (PMM) based on combination of various permeable and impermeable metallic materials interconnected by hot rolling in the vacuum. To create new materials, a combination of different types of metal grids is used. Therefore, these materials have received the name - combined porous mesh metals (CPMM). The technological problem is to create reliable products with predictable strength, filtration and structural characteristics. The technology of manufacturing products from CPMM is complex and includes a large number of technological operations divided into operations for material manufacture and operations for manufacturing from this material a finished product of required application. Material production includes several operations for preparing the initial metal grids (washing, degreasing, marking-out, grid packaging), and complex technological operations for material manufacturing, consisting in joint the grids and embedded materials between themselves (vacuuming, heating to a predetermined temperature, grid package rolling in vacuum and in hot condition, etc.). Each of technological operations for material manufacturing should be carried out in rigid mode ranges, such as temperature mode, package drafting degree mode, etc. A slight deviation from the mode leads to rejected material or significant deviation from the specified parameters. A difficult problem is the interconnection of metallic grids of various types (distinguishing by thickness, wire diameter, etc.), as well as interconnection of solid metallic embedded elements necessary for products formation from the obtained material. As a result of numerous experiments, it has been able to achieve success and develop the technology for CPMM material manufacturing. The developed material and products made from it have been imbedded at the enterprises of those industries, where highly reliable and efficient constructions, made from permeable materials and having specified functional parameters, are required. A new phase separator filter (PSF) for the fuel tank (FT) of a space item has been created and implemented. Currently, sets including 20 typical sizes of PSF of various modifications are delivered. Using of capillary intakes (CIs) with PSF made from CPMM provides reduction of residual rests of fuel liquid components in fuel tanks. CIs with PSF are almost 2 times lighter than CIs, carried out according to traditional frame-grid design.

STORING AN OVERSIZED MUSEU DE LISBOA TEXTILE BANNER COLLECTION

<p><strong>Abstract.</strong> In 1947 Lisbon held the "Cortejo Histórico de Lisboa", a parade belonging to the “VII Centenary of the Reconquest of Lisbon to the Moors” celebrations. For the accomplishment of this parade, hundreds of scenic objects and accessories were created and three thousand extras and actors participated. Museu de Lisboa has in its collection a significant set of these objects, with highlight to the seventeen-banner collection. These banners that since 1947 were kept in different warehouses, were transferred in 2008 to the Museu de Lisboa Central Storage Unit textile room. The large dimensions of these objects were the main preventive conservation issue the Museum had to solve, regarding the way of storing the collection. In 2018 the Museum designed a project for the vertical storage of these banners. Due to its enormous size (being the biggest 315&amp;thinsp;cm height and 212&amp;thinsp;cm width) it was impossible for the museum to store these objects in flat format. The alternative was designed and executed using <i>Tycore</i>® boards as backing panel, hinged with <i>acid-free</i> buffered paper sheets and then glued together into one large piece with the same size as each banner. The banners with textile strip extensions were mounted onto the panels and stored vertically on metallic grids used for the storage of the Museum painting art collection. Treatments such as dust cleaning, tear consolidation and stain removal were carried out to stabilize the banners prior to the mounting on the boards. This paper describes some of the steps of this eight-month project, involving six people.</p>

High-Directivity Antenna Array Based on Artificial Electromagnetic Metamaterials with Low Refractive Index

Planar metamaterials (MTMs) with low refractive index are proposed as a cover in a high-gain patch antenna array configuration. This MTMs array antenna has the following features: the number of array elements significantly decreases compared with the conventional array; the elements spacing is larger than a wave length by far; the feeding network is simpler. MTMs are made of two layers of periodic square metallic grids and placed above the feeding array. With the same aperture size, the directivity of MTMs-cover antenna array is higher than the conventional antenna array. The simulation results show that an array of 2 × 2 patch elements integrated with MTMs yields about 26 dB of directivity which is higher than that of conventional 8 × 8 patch array. Furthermore, on the condition of the same aperture size, an array patch with 4 × 4 elements integrated with the MTMs-cover has an equivalent gain compared with the conventional patch array with 16 × 16 array elements. Obviously, the former has a simpler feeding network and higher aperture efficiency. The experimental work has verified that the 2 × 2 array case and the measured results have good agreement with the simulation.

Investigation of grid metamaterial and EBG structures and its application to patch antenna

In this paper, we propose a new design of metamaterial and electromagnetic bandgap (EBG) structure based on double layers of metallic grids. Using finite integration technique, the electromagnetic properties of the grid structure have been investigated and this structure has been employed to enhance the performance of a patch antenna working at 11 GHz. The surface waves in the substrate of antenna have been suppressed by EBG behavior of the grid when used as a substrate, and it improves its gain to 9.21 dB from 5.64 dB. When this structure is also used as superstrate of the antenna, the gain up to 13 dB has been achieved due to its metamaterial behavior. Congregation effect of metamaterial provides a huge improvement in the directionality of the antenna and its half power beam width (HPBW) has been improved to 32.7° and 31.5° from 108.3° and 93.5° in E-and H-planes, respectively.